Charged with Thermal Trespass in Yellowstone? A Defense Attorney's Guide to 36 C.F.R. § 7.13(j)
Every year, visitors to Yellowstone National Park step off the boardwalk for a closer look, a better photo, or what they assume is harmless ground. What many do not realize is that putting a single foot into a thermal area can lead to federal criminal charges—and that those charges carry far more consequences than most people expect.
The list of people who have learned this the hard way is long, and it includes celebrities. Even James Bond himself—actor Pierce Brosnan—could not escape punishment for thermal trespass after he stepped onto a closed thermal feature at Mammoth Hot Springs and posted the photos to Instagram. He pleaded guilty in 2024 and was fined $500 plus a $1,000 donation to Yellowstone Forever (U.S. Department of Justice press release; CBS News coverage).
If a famous environmentalist who appeared in five Bond films cannot talk his way out of one of these citations, the average visitor should not expect to either. But that does not mean these cases are unwinnable—it means they require an attorney who understands how they work.
If you or a loved one has been cited for thermal trespass in Yellowstone, here is what you need to know.
What Is Thermal Trespass?
Thermal trespass is a federal offense charged under 36 C.F.R. § 7.13(j), the regulation that prohibits entering, walking on, or otherwise being present within Yellowstone's designated thermal areas. The charge is classified as a Class B petty misdemeanor under federal law. The maximum possible penalty for a Class B petty misdemeanor is up to 6 months imprisonment (18 U.S.C. § 3581(b)(7)), fine of up to $5,000 — or up to $250,000 if the offense results in death (18 U.S.C. § 3571(b)(6)), and probation up to 5 years (18 U.S.C. § 3561(c)(2)).
Thermal trespass may be cited whether you stepped onto a brittle geyser crust at Old Faithful, crossed a roped-off section near Mammoth Hot Springs, ventured into a back-basin thermal feature that was not obviously marked, or walked across snow-covered ground that turned out to be thermal terrain underneath.
The regulation exists for two reasons. The first is safety: the ground in hydrothermal areas is fragile and thin, and scalding water—often near boiling—sits just beneath the surface. People have been severely burned and even killed in Yellowstone's thermal features. The second is resource protection: a single footprint can leave a mark that lasts for decades. After one recent Texas defendant walked across several thermal features in the Mammoth Hot Springs area in late 2025, the park's geologist reported footprints pressed up to 12 centimeters deep into the delicate crust (Cowboy State Daily coverage).
Why Thermal Trespass Cases Are Harder to Beat Than Most Federal Charges
Thermal trespass cases are treated as strict liability offenses. That means the standard defenses people expect to raise simply do not apply:
It does not matter whether you saw a warning sign.
It does not matter whether you intended to enter a thermal area.
It does not matter whether you knew it was a thermal area.
It does not matter whether you believed the ground was safe.
If you were physically present in a thermal area, the government considers the elements of the offense met. This catches many visitors off guard—particularly those who assumed that an honest mistake, a missed sign, or unfamiliarity with the park would be enough to make the case go away.
Pierce Brosnan's own public statement after his citation captures the misunderstanding perfectly: he said he did not see a "No Trespassing" sign warning of danger when he entered the thermal area to take a photograph. In most trespass cases, that would be a meaningful fact. Under 36 C.F.R. § 7.13(j), it is not a defense.
What's at Stake
Both the United States Magistrate Judge who handles these cases at the Yellowstone Justice Center in Mammoth, Wyoming—Hon. Stephanie A. Hambrick—and the Assistant U.S. Attorney who prosecutes them—AUSA Ariel Calmes—take thermal trespass seriously. The reasons are not hard to understand: people have died in Yellowstone's hydrothermal features, and damage to the geothermal landscape can be permanent.
Penalties can include:
Fines, special assessments, and restitution
Probation
National Park Ban
Jail time in the most serious cases
Recent prosecutions show what the upper end looks like:
In 2024, a 21-year-old Washington man was sentenced to seven days in jail, a $1,500 fine, two years of unsupervised release, and a two-year ban from Yellowstone after he stepped off the boardwalk at Steamboat Geyser in the Norris Geyser Basin to take photographs (DOJ press release).
In 2019, two men who walked onto the cone of Old Faithful itself were each sentenced to ten days in jail, restitution, five years of probation, and a five-year ban from the park (National Park Service news release).
In 2026, a 50-year-old Texas man was sentenced to five days in jail after his footprints did "significant" damage across multiple thermal features (Cowboy State Daily).
For a single misstep on a hike, the consequences can follow a person for years—and can show up on background checks, security clearance reviews, and immigration screenings.
How Thermal Trespass Cases Are Actually Defended
Over the past five years, I have handled more thermal trespass cases in Yellowstone than any other defense attorney, and in that time I have obtained dismissals and collateral forfeitures for my clients. That track record reflects an approach built around the realities of how these cases are charged and prosecuted in the District of Wyoming.
1. Challenge whether the location qualifies as a "thermal area"
Strict liability only attaches if the cited location is, in fact, a thermal area under the regulation. The boundaries of these areas are not always obvious, particularly in winter when snow covers the ground, in back-basin or undeveloped areas, and along the edges of marked features where rangers and visitors may disagree about where the boundary actually lies. Where the geography is genuinely contestable, it should be contested. This often requires reviewing ranger photographs, GPS data, and park maps.
2. Build the strongest possible mitigation package
Because intent and knowledge are not defenses, mitigation is often the case. Effective mitigation can include:
A clean criminal history
Cooperation with rangers at the scene
Lack of damage to the resource (no visible footprints, no impact on the feature)
Minimal distance traveled in the thermal area
Whether the trespass involved a social/game trail
Absence of clear signage at the actual point of entry
Conditions that obscured the boundary (snow cover, darkness, weather)
Genuine remorse and acceptance of responsibility
Voluntary community service or donations to park conservation organizations
Strong character references and employment history
The more compelling the mitigation, the more leverage there is at every stage of the case. AUSA Calmes and Judge Hambrick both pay close attention to whether a defendant treated the citation as a serious matter from the beginning or treated it as a minor inconvenience to be brushed off.
3. Push for dismissal—and if not, for a collateral forfeiture
The best outcome is always outright dismissal. When dismissal is not on the table, the next-best result is a collateral forfeiture: the defendant pays an agreed amount and the case resolves without a criminal conviction on the record. Collateral forfeitures are difficult to obtain in thermal trespass cases—the U.S. Attorney's Office does not offer them lightly—but they are sometimes available when the mitigation is strong, the facts allow for it, and the case is presented to the prosecutor in the right way. Avoiding a conviction matters far beyond the immediate case, particularly for clients with professional licenses, security clearances, immigration concerns, military or government employment, or future plans involving federal land.
4. Prepare seriously for sentencing if it comes to that
If a case has to be resolved by plea, sentencing is where the work pays off. A mitigation package that has been built carefully from day one is the difference between a fine and probation—and between probation and jail.
Common Scenarios That Lead to Thermal Trespass Citations
Most clients are not reckless rule-breakers. The typical citation arises from situations like:
Stepping off a boardwalk for a photograph, especially at heavily visited features like Old Faithful, Grand Prismatic, and Mammoth Hot Springs. This is what got Pierce Brosnan cited.
Winter and shoulder-season hikes where snow obscures thermal boundaries and warning signs.
Back-basin and off-trail exploration in areas where visitors do not realize they are inside a thermal zone.
Following someone else's footprints, on the assumption that if another person walked there, it must be safe and legal.
Children wandering into closed areas while adults are nearby.
Social media-driven choices—stepping into a frame for a photo or video that gets uploaded and later spotted by rangers, as happened in the Brosnan case.
None of these scenarios is a legal defense. All of them can become part of a strong mitigation narrative.
Why Experience in This Specific Court Matters
Thermal trespass cases are not generic federal misdemeanors. They are prosecuted in a specific courtroom, by a specific AUSA, in front of a specific judge, under a regulatory scheme that very few attorneys outside this district encounter regularly. Knowing how Judge Hambrick approaches mitigation, what AUSA Calmes is and is not willing to negotiate, how rangers document these citations, and how the U.S. Attorney's Office for the District of Wyoming weighs different fact patterns is the difference between an effective defense and a generic one.
Frequently Asked Questions
Do I have to come back to Wyoming for court? In most cases, no—that is, unless you proceed to a bench trial or file a motion that involves witness testimony. Most matters can be handled remotely or by counsel, but Judge Hambrick generally expects defendants to appear by Zoom if they are representing themselves or the case proceeds to sentencing. An experienced attorney can often minimize the number of appearances required.
Will this show up on a background check? A charge or conviction under 36 C.F.R. § 7.13(j) is a federal misdemeanor and can appear on background checks.
Can I just pay the ticket and be done with it? Sometimes—but in most cases no. These cases are generally cited as “Must Appear” meaning that it is mandatory that you appear in court.
What about a national park ban? Bans are real and can happen. However, they only apply to Yellowstone National Park, not all national parks. They are negotiable in some cases and not in others.
Does this affect my immigration status? It can. Any non-citizen cited for thermal trespass should speak with an attorney who understands both criminal and immigration consequences before entering any plea.
If You Have Been Cited
Do not assume a thermal trespass citation will resolve itself with a quick guilty plea and a fine. The collateral consequences can be more serious than the citation appears on its face, and the window to build effective mitigation is short. Once a plea is entered, options narrow dramatically.
Contact Teton Defense to discuss your case. My experience in these cases means you will know exactly what you are facing—and what realistic outcomes are available to you.
